Ireland takes its lead on the UK’s Brexit position from the Prime Minister, not Boris Johnson, the Irish deputy premier has said.

Simon Coveney was responding to the Foreign Secretary’s scathing assessment of a proposed customs partnership between the UK and the EU as “crazy”.

Mr Coveney said Theresa May’s vision of a partnership – where the UK collects tariffs on behalf of Brussels – could provide the basis for negotiating a solution to the vexed problem of maintaining a free flowing Irish border.

Talks continue over the Irish border issue (Brian Lawless/PA)

Responding to the remarks, Democratic Unionist MP Sammy Wilson, one of Mr Coveney’s most vocal critics, branded him “belligerent, interfering and Brit bashing” and accused him of trying to break up the UK.

The UK cabinet is currently divided on the issue, with detractors of the partnership concept instead advocating new technology and trusted trader schemes to enable smooth trade with the EU.

Mr Johnson has been very critical of the idea of a partnership or shared customs territory, insisting it would prevent the UK taking back control of its trading policies.

Mr Coveney said the UK had made a clear commitment in last December’s agreed UK/EU text that there would be no physical infrastructure on the border.

“That means we are not talking about cameras and scanning systems and drones here – it means we are talking about a political solution that allows for regulatory alignment in a way that prevents the need for border infrastructure,” he said.

He added: “We are simply asking that that commitment be followed through on.”

Tanaiste Mr Coveney told The Andrew Marr Show on BBC One: “To be honest we don’t take our lead from Boris Johnson in relation to Brexit, we take our lead from the Prime Minister.

“She has signed up to very clear commitments, she has written to Donald Tusk (European Council President) confirming those commitments and I believe her by the way, I believe she made those commitments in good faith and I believe she wants to follow through on them.”

He said Brexit negotiations would face a “difficult summer” if the UK Government failed to honour its commitment to agreeing a “backstop” in the withdrawal treaty.

The backstop would mean regulations between Northern Ireland and the Irish Republic would continue to align post-Brexit, even if a broader trading deal between the UK and EU failed to materialise.

This concept has alarmed unionists, who believe it would end up creating trading barriers between Northern Ireland and the rest of the UK, undermining the constitutional integrity of the kingdom.

Those sensitivities are particularly pertinent to Mrs May, as her government’s survival relies on a confidence and supply deal with the Democratic Unionists at Westminster.

Dismissing claims the Irish were overplaying the border issue, Mr Coveney insisted maintaining a seamless frontier was about more than just trade.

“If you live in the island of Ireland, if you live in the border counties, if you talk to people about their memories of the past in the context of the border you will often end up talking to someone with tears in their eyes,” he said.

“This is not just a trading issue – this is about Ireland moving forward, communities and neighbours living together.”

“The fact is that the border issues can all be dealt with by technology but Coveney and Co have stuck their heads in the sand, refusing to even consider this solution because it doesn’t suit his aggressive republican agenda,” he said.

“Instead he tried to flog his ‘pig in a poke’ solution to the EU negotiators and force it down the throat of the UK Government.

“It won’t work. The IRA failed to dislodge Northern Ireland from the UK with bombs, Coveney won’t do it with Brexit.

“The UK always has the option to walk away from these negotiations with no deal.

“That really would set the cat among the pigeons as far as the Irish economy is concerned because most of their exports to the UK would face huge tariffs and of course the import substitution which would result would massively benefit Northern Ireland agriculture and food processing.

“Think about that Mr Coveney – it might cool your republican ardour.”

Mr Coveney later held talks with French foreign minister Jean-Yves Le Drian in Dublin.

The Tanaiste said the customs partnership “doesn’t solve all problems” but he said it could pave the way for an arrangement that avoided the need for customs checks on the border.

“It is difficult to talk in detail and in substance about a customs partnership unless we know that is the approach (from the UK) to the negotiations,” he said after the meeting with Mr Le Drian.

Mr Coveney added: “People now seem to be essentially redesigning what has already been committed, so we are simply saying we want to see the follow through on the commitments that have been made in December and March.

“We would like to see substantial progress on that by the end of June.

“And I don’t think it unreasonable to ask a British government to follow through on commitments they have already made.”

Mr Le Drian made clear that the issue had to be resolved by June’s EU summit, or shortly thereafter.

“There is a solution today on the border issue – which is the backstop,” he said.

“This has been validated. If there are other options they have to be tabled so we can check they match the initial commitments – and the initial commitments are the refusal of a physical border coming once again and respecting the Good Friday Agreement.”

He added: “The June deadline is the deadline that must be seen as the ultimate deadline.

“I know there is a little bit more time afterwards but the schedule is very tight so this issue is absolutely essential and we wish to reach an agreement.

“If there is no validated position then the withdrawal agreement will be more complex so we have to push in this way.”